Leaking Toilet Attachment

When tiolets wobble they can eventually leak.  This Reston Virginia toilet did both.  The leak was pooling behind the refrigerator and not noticed for some time.  You can see why this one wobbled - the flange is screwed into very little.  Looking closely you can see three different drywall screws.  What should have been used were stainless steel screws and they should anchor securely to thick subflooring. The plywood used here is 5/16ths of an inch, much too small.  At least the "plumber" used purple primer...